JPS6042736A - Illumination assay diagnostic method - Google Patents

Abstract

PURPOSE:To execute exactly a diagnosis of abnormality in an illumination assay by comparing the variation pattern of a 0-order optical output in the illumination assay passing an optical modulator, with the variation pattern of a video signal, and detecting the difference of both variation patterns. CONSTITUTION:A sensor 8 is provided on the passing optical path of a 0-order light L0 in the outputs of the optical modulator 20 in the illumination assay 100, and also, an abnormality detecting circuit 9 of an illumination assay is provided on the outside of the illumination assay 100. This abnormality detecting circuit 9 consists of a delaying circuit 91, a binary-coding circuit 92 and a comparing circuit 93, and a photoelectric transducing output of the 0-order light L0 detected by the optical sensor 8 is provided to the binary-coding circuit 92 first, binary- coded by the threshold of a constant level, and thereafter, provided to the comparing circuit 93. A video signal VS is applied to the delaying circuit 91 of the abnormality detecting circuit 9 first, delayed by a prescribed time, and thereafter, applied to the comparing circuit 93.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of industrial application] The present invention relates to oscillation of a laser oscillator in an illumination assembly including at least a laser oscillator and an optical modulator that modulates laser light emitted from the laser oscillator. The present invention relates to an illumination assembly diagnostic method for detecting an abnormality or a modulation abnormality of the optical modulator.

[Prior art]

FIG. 1 is a schematic diagram showing a general configuration example of a laser scanning optical system used in a facsimile machine, a laser printer, etc., and includes a Rade oscillator 1 and an optical modulator 2.

The illumination assembly 100 includes a mirror 3 and a lens 4, a scanner assembly 200 includes a rotating polygon mirror 5 and a cylinder lens 6, and a photosensitive drum 7. Recording scanning in such a laser scanning optical system is performed by the following method. First, a predetermined amount of laser light oscillated from a laser oscillator 1 enters an optical modulator 2, and is modulated by a video signal 8 applied to the optical modulator 2, resulting in zero-order light that travels straight without being deflected. It is polarized and output as primary light containing optical image information. Among these Ryokawa forces, the primary light containing the optical image information is the mirror 3. The light is guided through a lens 4 to one deflection surface of a rotating polygon mirror 5, is deflected as the rotating polygon mirror 5 rotates, and is scanned in a fixed direction on a photosensitive drum 7 through a Schilling lens 6. By such rotation of the rotating polygon mirror 5, the above 1
The scanning of the secondary light is sequentially performed on each deflection opening of the rotating polygon mirror 5 to form a latent image on the photoreceptor 1° ram 7 in accordance with the image information of the primary light. Thereafter, image information based on the latent image is recorded by sequentially passing through developing, transferring, fixing, and cleaning mechanisms (not shown) provided on the outer periphery of the photosensitive drum 7. By the way, detection of various abnormalities occurring in the laser scanning optical system having such a configuration has conventionally been carried out by the following diagnostic method. That is, 8 shown in FIG. 1 is an optical sensor provided in a space physically equivalent to the scanning start position of the photoreceptor drum 7, and the optical sensor 8 detects the rotation of the rotating polygon mirror 5 as described above. Scanning is started at each scan of the laser beam by receiving the laser beam to be scanned, detecting the optical conversion output according to the light location, and monitoring the presence or absence of the photoelectric conversion output or changes in the output level. We were diagnosing misalignment or abnormal laser power output. However, when the conventional diagnostic method is applied to a laser scanning optical system composed of two independent sub-assemblies, the illumination assembly 100 and the scanner assembly 200, the scanner assembly 200 actually
For example, when the radar light is not being scanned due to a failure in the drive system of the rotating polygon mirror 5, the optical sensor 8 cannot receive a received light output, and this state causes an abnormality in the illumination assembly 100 (the laser oscillator). This is detected as an oscillation abnormality in the optical modulator 2 or a modulation abnormality in the optical modulator 2), making it impossible to accurately diagnose the abnormality in units of subassemblies.゛Also, the laser light detection section including the optical sensor 8 detects the state where the photoelectric conversion output is "present" on the optical sensor 8, that is, the state where the laser light is always incident, as "normal", so the above is not true. On the contrary, the optical modulator 2 becomes, for example, modulated and the illumination assembly 1o.

Even if there is an abnormality in the illumination assembly 1, the light reception output of the optical sensor 8 remains in the "present" state.
There was also a drawback that abnormalities of 00 could not be detected.

[Purpose of the invention]

The present invention has been devised to eliminate the above-mentioned drawbacks, and is effective in detecting abnormalities in the modulation of the modulator without being affected by the operational status of the scanner assembly (for example, abnormal scanning). It is an object of the present invention to provide an illumination assembly diagnostic method that can accurately and reliably perform abnormality diagnosis on a unit basis, especially within an illumination assembly.

[Structure of the invention]

Therefore, in the present invention, among the outputs of the optical modulator, V=
Focusing on the zero-order light that is outputted in a straight line without being reflected and is not reflected in the deflection of the recording scanning end in the scanner array 7-, the optical sensor is newly installed in the optical path of the zero-order light in the illumination assembly, and the A change in the received light output of the zero-order light obtained from the optical sensor is compared with a change in the video signal, and an abnormality in the illumination assembly is determined by the output when a difference occurs in the change pattern between the two. The above purpose is achieved by detecting.

[Embodiments of the invention]

An embodiment of the present invention will now be described in detail 1 based on the accompanying drawings. FIG. 2 is a schematic diagram showing an example of the configuration of a laser scanning optical system to which the illumination assembly diagnostic method of the present invention is applied. Components that perform the same functions as those of the conventional device shown in FIG. 1 have the same reference numerals. It is marked.

According to the laser scanning optical system of the present invention, the optical sensor 8
The optical modulator 2 in the illumination assembly lOO
The new features include that the illumination assembly abnormality detection circuit (hereinafter simply referred to as abnormality detection circuit) 9 is provided outside the illumination assembly 100 and provided in the optical path through which the O-order light Lo among the zero outputs passes. In the laser scanning optical system of the present invention, the optical modulator 20
A video signal V8 is applied to both the abnormality detection circuit 9 from an image information supply circuit (not shown).

On the other hand, the laser beam oscillated from the laser oscillator l is incident on the optical modulator 20. Therefore, the optical modulator 20 modulates the laser beam with the video signal V8 applied as described above and outputs it as the zero-order light Lo or the first-order light Ll. Here, the zero-order light Lo is laser light that has not been modulated by the optical modulator 20, and is output straight along the incident optical path from the Rade oscillator I. In addition, the primary light L1
is a laser beam containing optical image information modulated by the optical modulator 20, and is output after being deflected at a predetermined angle. Since the light intensity of the modulated laser beam emitted from the laser oscillator 1 is constant, the light intensity of these O-order light Lo and the first-order light L1 is, for example, as the light intensity of the zero-order light Lo increases, the first-order light L1 increases.
The light intensity of the light modulator 20 is modulated by the video signal VB in such a manner that the light intensity of the first dimension L1 decreases, and conversely, when the light intensity of the ()-order light Lo decreases, the light intensity of the one-dimensional L1 increases. It is something that receives. Therefore, the relationship between these photoelectric conversion outputs and the video signal can be expressed isometrically by time charts as shown in FIGS. 3(,) to (c). That is, the photoelectric conversion output of the primary light beam for the video signal v8 shown in FIG. 3(,) shows the same characteristics as the video signal VS as shown in FIG. 3(b).
The photoelectric conversion output of the O-order light Lo exhibits a completely inverted characteristic to the former characteristic, as shown in FIG. 3(c).

Generally, the primary light L1 of the above-mentioned Rede light is used to form a latent image on the photoreceptor drum 7 according to image information. That is, the primary light that has been modulated and deflected by the optical modulator 20 as described above first enters the mirror 3, is reflected, passes through the lens 4, and is deflected as the rotating polygon mirror 5 rotates until it reaches the entire cylinder lens 6. The photoreceptor drum 7 is scanned in a fixed direction through the laser beam, forming a latent image according to the image information of the laser beam. Here, the cylinder lens 6 functions to correct the positional deviation of the laser beam in the direction perpendicular to the scanning direction of the laser beam by the rotating polygon mirror 50 as described above. On the other hand, the zero-order light Lo output from the optical modulator 20 without being deflected travels straight along the optical path of the modulated laser beam irradiated from the laser oscillator l, enters the optical sensor 8, and is detected by the optical sensor 8. The photoelectric conversion output is converted into an abnormality signal and is further guided to the abnormality detection circuit 9. FIG. 4 is a block diagram showing an example of the configuration of this abnormality detection circuit 9, including a delay circuit 91, a binarization circuit 92, and so on. It consists of a comparison circuit 93. As described above, the photoelectric conversion output of the zero-order light Lo detected by the optical sensor 8 is first applied to the binarization circuit 92, binarized with a threshold value of a certain level, and then applied to the comparison circuit 93. . On the other hand, the above-mentioned video signal V8 is first applied to the delay circuit 91K of the abnormality detection circuit 9, delayed by a predetermined time, and then applied to the comparison circuit 93. The video signal V here
The delay of s is the comparison input with the video signal Vs.
This is done in order to correct the delay in the manual timing of the binary output of the secondary light Lo to the comparison circuit 93 due to the AiJ optical variable modulator 20 adjustment, and by making this delay correction, the comparison circuit 93 said video signal v8 to 93
and zero-order light. The input timings of the binarized outputs are matched to enable the comparison described below. As mentioned above, normally, that is, when the laser oscillator 1 and the optical modulator 20 are performing normal oscillation and modulation operations, the photoelectric conversion outputs of the video signal Vs and the O-order light Lo have characteristics that are opposite to each other. , and the change pattern is the same. However, if for some reason an oscillation abnormality occurs in the laser oscillator 1 or a modulation abnormality in the optical modulator 20, that is, if an abnormality occurs in the illumination assembly 100, the zero-order light Lo will also be affected by this. 2 of the photoelectric conversion output of the zero-order light Lo that changes and is naturally applied from the binarization circuit 92 to the comparison circuit 93.
Value outputs also often exhibit characteristics different from those described above. Therefore, the comparison circuit 93 searches for the state of change in the binary output of the input video signal Vs and the photoelectric conversion output of the O-order light Lo as described above, and when a difference occurs in the output pattern of these two, the illumination assembly is abnormal. Outputs a detection signal. Outside the abnormality detection circuit 9, this abnormality detection output causes an alarm to sound or an abnormality display to notify the operator that an abnormality has occurred in the illumination assembly 100. By the way, the abnormality of the illumination assembly 100 and 1. In addition to the oscillation abnormality of the laser oscillator l and the modulation abnormality of the optical modulator 20 described above, the mirror 3
．． This includes factors such as failure of the lens 4, but the mirror 3. There is almost no need to think about the failure of the lens 4 from a structural point of view. For this reason, an operator who learns of an abnormality in the illumination assembly 100 only needs to inspect predetermined locations of the laser oscillator 1 and optical modulator 20, identify the abnormality, and take countermeasures against the abnormality. In this way, the optical sensor 8 is disposed in the optical path of the O-order light L0 of the optical modulator 20 in the illumination assembly 100, and the photoelectric conversion output of the O-order light Lo obtained from the optical sensor 8 is binarized. In order to compare the change turn between the binarized output and the above-mentioned Bigao Hakugo vl, and to diagnose an abnormality in the illumination assembly based on the difference in output pattern between the two, the optical sensor 8 is connected to the photoreceptor drum. Arranged on the circumference of 7 [
7.Compared to the conventional method of diagnosing an abnormality based on the level and turn of the detection output of the optical sensor, this condition cannot be detected by the illumination assembly because it cannot receive the light due to the inability of the rotating polygon mirror to rotate. It may be diagnosed as an abnormality, or the optical modulator may be modulated (~
Since the laser beam can always be received when this state occurs, it is possible to avoid a misdiagnosis in which this state cannot be diagnosed as an abnormality.

〔Effect of the invention〕

As explained above, according to the illumination assembly diagnostic method of the present invention, the nine turns of change in the zero-order light output within the illumination assembly after passing through the optical modulator are compared with the change pattern of the video signal, and the two are compared. change·
Illumination Ara 7-
Since it is possible to detect abnormalities in the illumination assembly without being affected by the operating status of the scanner assembly, it is also effective in detecting abnormalities in the optical modulator, so it is possible to detect abnormalities in the illumination assembly without being affected by the operating status of the scanner assembly. The excellent effect of realizing accurate functional diagnosis can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a laser scanning optical system to which a conventional abnormality diagnosis method is applied, FIG. 2 is a schematic configuration diagram of a radar scanning optical system to which the illumination assembly diagnosis method of the present invention is applied, and FIG. FIG. 2 is a time chart showing various signals in each part of the laser scanning optical system shown in an equally economical manner, and FIG. 4 is a block diagram showing an example of the configuration of an illumination assembly abnormality detection circuit according to the present invention. 1... Laser oscillator, 2.20... Optical modulator, 3.
...Mirror, 4...Lens, 5...Rotating polygon mirror, 6
... Cylinder lens, 7... Photosensitive drum, 8...
- Optical sensor, 9... Illumination assembly abnormality detection circuit, 91... Delay circuit, 92... Binarization circuit,
93... Comparison circuit. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] An illumination assembly' comprising a laser oscillator and an optical modulator that modulates the laser light emitted from the laser oscillator with a specific video signal and outputs it as zero-order light and first-order light with different deflection angles, respectively; and the optical modulator. In an illumination assembly diagnostic method in a laser scanning optical system having a scanner assembly that scans the first-order light outputted from a device, a change state of the photoelectric conversion output of the zero-order light not used by the scanner assembly and a change state of the photoelectric conversion output of the zero-order light and the video signal. A method for diagnosing an illumination assembly, characterized in that the illumination assembly diagnosis method is characterized in that when the two change states are different and the two change states are different and the case is 7'C, it is determined as an abnormality in the illumination up.